The internet and its uses flashcards

Topic 5: The internet and its uses

What is the difference between the internet and the World Wide Web?

The internet is the global network of interconnected networks (the infrastructure). The World Wide Web is a collection of web pages and resources stored on web servers and accessed using the internet.

What are the parts of a URL?

The protocol (e.g. https), the domain name (e.g. www.example.com) and usually a path and file name (e.g. /shop/boots.html).

HTTP vs HTTPS

HTTP is the protocol used to request and send web pages. HTTPS is the secure version: it encrypts the data using SSL/TLS, so intercepted data cannot be read.

How does the DNS find a web page?

The browser sends the domain name to a DNS server, which looks up the matching IP address (asking other DNS servers if needed) and returns it. The browser then requests the page from the web server at that IP address.

Session cookie vs persistent cookie

A session cookie is held in memory and deleted when the browser closes, e.g. to keep a shopping basket. A persistent cookie stays on the device until it expires or is deleted, e.g. to remember logins or preferences.

What is a blockchain?

A digital ledger of transactions held as a chain of blocks, shared across many computers. Each block holds transactions, a timestamp, its own hash and the hash of the previous block, so changing a past block breaks the chain and is detected.

What is a DDoS attack, and how can it be prevented?

Distributed denial of service: many computers flood a server with requests so genuine users cannot get through. Defences include a firewall, traffic filtering and proxy servers.

Phishing vs pharming

Phishing: fake emails or messages pretending to be from a trusted source trick the user into giving personal data. Pharming: malicious code redirects the user to a fake website even when the correct URL is typed.

What is a brute-force attack, and how is it prevented?

Trying many passwords or keys in turn until one works. Prevent it with long, complex passwords, a limit on login attempts and two-factor authentication.

Name five types of malware

Any five of: virus, worm, trojan horse, spyware, adware, ransomware.